Twelve year old boys are not precocious, they are already in puberty. Precocious puberty usually occurs in the age group of eight or nine years old, and twelve years old is already in puberty. At this time the male is in the stage of rapid development, the sex organs will develop, began to appear penis enlargement, thickening, testicular development and enlargement, the scrotum appears pubic hair growth, the voice gradually thicker, due to the gradual development and maturation of the sex organs, some boys may have spermatorrhea, as well as morning erections and other manifestations. Twelve-year-old boys due to the rapid development of the body, may lead to some of the body’s nutrient supply is insufficient, to pay attention to timely supplementation, and usually pay attention to more strengthen exercise, develop good habits.